CivilKit RC Sections
Rectangles, circles, T-beams, hollow boxes and columns, with voids and any bar layout. Every result updates as you type, and the same section is one click away as Python you can edit and run in the page.
Runs in your browser. No install, no sign-up.
Section properties, exact
Area, centroid, second moments, principal axes and section moduli integrated exactly over the outline and its voids, plus the transformed gross and cracked sections.
Moment-curvature to failure
Play or scrub the curve and watch the concrete stress, the bar stresses and the neutral axis move until the concrete crushes or a bar fractures.
AS 3600 M-N interaction
The Cl 10.6.2 diagram with the Cl 8.1.3 stress block and Table 2.2.2 capacity factors, nominal and design, with a point check for your N* and M*.
Biaxial bending
The ultimate Mx-My contour at any axial load, for sections that are not symmetric or not loaded about a principal axis.
Drop to code
Open the code drawer to get the section as Python, edit it, run it in the page and send the result back to the drawing. Nothing to install.
Checked against an independent engine
Properties, moment-curvature, AS 3600 capacities and biaxial bending are compared against the open-source concreteproperties library over 24 sections in our test suite.
CivilKit RC Sections assists a qualified engineer; it does not replace one. Outputs must be checked against project requirements, applicable standards and site conditions before use in construction. Certification and sign-off remain with the registered engineer of record.